Sounds like a pretty thin excuse to me. By 1865 there was very little left of the confederacy to plant anything in.
Indeed, there was a shortage of food already among the Confederate troops, and Grant's soldiers gave them food after the surrender.
The shortage of food and supplies is a popular myth. The fact of the matter is that the confederacy never suffered from a lack of food, and for the most part sufficient supplies were available. What it did suffer from was a poor transportation network and an inept commissary department, headed, as might be expected, by a friend of Jefferson Davis. When John Breckenridge took over the war department in January 1865 he fired the man and replaced him with a competent administrator. During the last months of the war, Breckenridge had no problem accumulating sufficient food and forage for the army but remained hampered by a transportation network that didn't allow him to get the stuff from point A to point B.
There is some truth in what you say, but the effect on the hungry person is the same whether there is insufficient food or a poorly functioning transportation system that can't get the food to him.
Here's one description of what was going on [Link]:
Shortages of food--probably the result of inadequate distribution systems rather than actual absolute shortfalls--plagued many soldiers' wives and children. Cloth production was imperiled both by absence of raw materials and by the Confederacy's inability to manufacture the cotton cards essential for home clothing manufacture. A Georgia grand jury proclaimed in August 1862, "We are grieved and appalled at the distress which threatens our people especially the widows and orphans and wives and children of our poor soldiers." An official in Alabama noted that in parts of the state citizens were actually dying of starvation.
… In some areas of North Carolina, for example, as many as 40% of white women received government support to relieve hunger and deprivation.
… Women, too, became embroiled in the controversy --most notably in bread riots that erupted in Richmond and locations across the Confederacy in 1863 and later. An eloquent but barely educated North Carolina woman named Nancy Mangum wrote feelingly to Governor Zebulon Vance in 1863: "I have threatened for some time to write you a letter--a crowd of we poor women went to Greensborough yesterday for something to eat as we had not a mouthful meat nor bread--what did they do but put us in jail--we women will write for our husbands to come home and help us."
There were 3,000 ladies in the 1863 Richmond bread riot. Let's look for a minute at how the war affected the transportation system:
One of the greatest calamities which confronted Southerners was the havoc wrought on the transportation system. Roads were impassable or nonexistent, and bridges were destroyed or washed away. The important river traffic was at a standstill: levees were broken, channels were blocked, the few steamboats which had not been captured or destroyed were in a state of disrepair, wharves had decayed or were missing, and trained personnel were dead or dispersed. Horses, mules, oxen, carriages, wagons, and carts had nearly all fallen prey at one time or another to the contending armies. The railroads were paralyzed, with most of the companies bankrupt. These lines had been the special target of the enemy. On one stretch of 114 miles in Alabama, "every bridge and trestle was destroyed, cross-ties rotten, buildings burned, water-tanks gone, ditches filled up, and tracks grown up in weeds and bushes." Sherman's men had destroyed all railroad equipment within reach -- 136 of 281 miles of the Central of Georgia, alone -- and added the novelty of twisting heated rails around trees. In Alabama nearly all of its 800 miles of railway was useless. One Mississippi line reported fit for use, though damaged, a total of one locomotive, two second-class passenger cars, one first-class passenger car, one baggage car, one provision car, two stock cars, and two flat cars. Communication centers like Columbia and Atlanta were in ruins; shops and foundries were wrecked or in disrepair. Even those areas bypassed by battle had been pirated for equipment needed on the battlefront, and the wear and tear of wartime usage without adequate repairs or replacements reduced all to a state of disintegration. Not for a generation were the railroads properly restored, and then largely by Northern capital. [Link] (It's Wikipedia, I know, but the above quote is out of a book they cite.)
Now lets look at what Northern troops did to the local food supply:
South Carolina: After a comment upon these outrages, the writer gives a sketch of the devastation occasioned on the route taken by the enemy [the Yanks, who else], some portion of which we copy:
"Leaving our town, the enemy took their line of march on the State road, leading to Blackstock's, South Carolina. On the route, their road can be easily distinguished by tall chimneys, standing solitary and alone, and blackened embers, as it were, laying at their feet. --Every fine residence, all corn cribs, smoke-houses, cotton-gins — all that could give comfort to man — were committed to the flames; dead animals — horses, mules, cows, calves and hogs — slain by the enemy, are scattered along the road to Blackstock's.
"In one place we counted fourteen fine milch cows, with their young, lying in the space of a half-acre field, having been shot. To show with what brutality they even treated dumb creatures, we discovered two calves hung with telegraph wire, and left in that position to die of utter starvation. Others again had wire ingeniously wound around the leg and neck in such a position that, in walking, the jagged end of the wire would penetrate the throat; and so they died by slow torture. [Source: The Daily Dispatch, Richmond, Virginia, January 24, 1865]
Georgia: In their route they [Sherman's troops] destroyed, as far as possible, all mills, cribs, and carried off all stock, provisions, and negroes, and when their horses gave out they shot them. At Canton they killed over 100. ... All along their route the road was strewn with dead horses, Farmers having devoted a large share of their attention to syrup making, there is a large quantity of cotton ungathered in the field, which was left by Federals, but there is not a horse or ox in the country, hence the saving of corn will be a difficult matter.
On going to McCradle's place he [a Georgia legislator] found his fine house and ginhouse burned, every horse and mule gone, and in his lot 100 dead horses, that looked like good stock, that were evidently killed to deprive the planters of them.
...No farm on the road to the place, and as far as we hear from toward Atlanta, escaped their brutal ravages. They ravaged the country below there to the Oconee River. The roads were strewn with the debris of their progress. Dead horses, cows, sheep, hogs, chicken, corn, wheat, cotton, books, paper, broken vessels, coffee mills, and fragments of nearly every species of property strewed the wayside.
...They gutted every store, and plundered more or less of everything. ... Many families have not a pound of meat or peck of meal or flour. [Source: The Daily Picayune of New Orleans]
Virginia: The full mobilization of Augusta County [Virginia] in 1864 left little room for further expansion of the war effort. According to one woman in February 1864 the only white men left were older farmers who she predicted would not join the army even if drafted. "I say it seams starvation will end it anyhow," she wrote, "there is a number of farms that there is not a man on. if the farms are stopped I think the war must stop. they cant fight without bread." She concluded, "I think the southern confederacy has gone nearly up the spout." [Link]